Sound Proofing Material With Improved Damping And Structural Integrity

ABSTRACT

Panels for use in building construction (partitions, walls, ceilings, floors or doors) which exhibit improved acoustical sound proofing in multiple specific frequency ranges and also present improved structural integrity, are provided. The improved performance is achieved through the use of one or more layers of glue such that at least one layer of glue includes a viscoelastic material in a first pattern and a structural adhesive in a second, non-overlapping pattern. The viscoelastic material may have a varied shear moduli and functions as a glue and energy dissipating layer. In some embodiments, one or more constraining layers separating one layer of glue may be included. The constraining layer may be formed of a material such as gypsum, cement, metal, cellulose, wood, or petroleum-based products such as vinyl, plastic, or rubber. In some embodiments, standard wallboard, typically gypsum, comprises the external surfaces of the laminated panel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to, and the benefit of, co-pending U.S. patent application Ser. No. 11/772,197 filed in the US Patent and Trademarks Office on Jun. 30, 2007, the entire contents of which are incorporated herein by reference. This application also claims priority to, and the benefit of, co-pending U.S. patent application Ser. No. 11/734,770 filed in the US Patent and Trademarks Office on Apr. 12, 2007, the entire contents of which are incorporated herein by reference. This application also claims priority to, and the benefit of, co-pending U.S. patent application Ser. No. 11/607,190 filed in the US Patent and Trademarks Office on Nov. 30, 2006, the entire contents of which are incorporated herein by reference.

BACKGROUND

Noise control constitutes a rapidly growing economic and public policy concern for the construction industry. Areas with high acoustical isolation (commonly referred to as ‘soundproofed’) are requested and required for a variety of purposes. Apartments, condominiums, hotels, schools and hospitals all require rooms with walls, ceilings and floors that reduce the transmission of sound thereby minimizing, or eliminating, the disturbance to people in adjacent rooms. Soundproofing is particularly important in buildings adjacent to public transportation, such as highways, airports and railroad lines. Additionally theaters, home theaters, music practice rooms, recording studios and the like require increased noise abatement. Likewise, hospitals and general healthcare facilities have begun to recognize acoustical comfort as an important part of a patient's recovery time. One measure of the severity of multi-party residential and commercial noise control issues is the widespread emergence of model building codes and design guidelines that specify minimum Sound Transmission Class (STC) ratings for specific wall structures within a building. Another measure is the broad emergence of litigation between homeowners and builders over the issue of unacceptable noise levels. To the detriment of the U.S. economy, both problems have resulted in major builders refusing to build homes, condos and apartments in certain municipalities; and in widespread cancellation of liability insurance for builders. The International Code Council has established that the minimum sound isolation between multiple tenant dwellings or between dwellings and corridors is a lab certified STC 50. Regional codes or builder specifications for these walls are often STC 60 or more. It is obvious that the problem is compounded when a single wall or structure is value engineered to minimize the material and labor involved during construction.

It is helpful to understand how STC is calculated in order to improve the performance of building partitions. STC is a single-number rating that acts as a weighted average of the noise attenuation (also termed transmission loss) of a partition across many acoustical frequencies. The STC is derived by fitting a reference rating curve to the sound transmission loss (TL) values measured for the 16 contiguous one-third octave frequency bands with nominal mid-band frequencies of 125 Hertz (Hz) to 4000 Hertz inclusive, by a standard method. The reference rating curve is fitted to the 16 measured TL values such that the sum of deficiencies (TL values less than the reference rating curve), does not exceed 32 decibels, and no single deficiency is greater than 8 decibels. The STC value is the numerical value of the reference contour at 500 Hz. For maximum STC rating, it is desirable for the performance of a partition to match the shape of the reference curve and minimize the total number of deficiencies.

An example of materials poorly designed for performance according to an STC-based evaluation is evident in the case of many typical wood framed wall assemblies. A single stud wall assembly with a single layer of type X gypsum wallboard on each side is recognized as having inadequate acoustical performance. That single stud wall has been laboratory tested to an STC 34—well below the STC 50 building code requirement. A similar wall configuration consisting of two layers of type X gypsum wall board on one side and a single layer of type X gypsum board on the other is an STC 36—only a slightly better result.

Various construction techniques and products have emerged to address the problem of noise control, such as: replacement of wooden framing studs with light gauge steel studs; alternative framing techniques such as staggered-stud and double-stud construction; additional gypsum drywall layers; the addition of resilient channels to offset and isolate drywall panels from framing studs; the addition of mass-loaded vinyl barriers; cellulose-based sound board; and the use of cellulose and fiberglass batt insulation in walls not requiring thermal control. All of these changes help reduce the noise transmission but not to such an extent that certain disturbing noises (e.g., those with significant low frequency content or high sound pressure levels) in a given room are prevented from being transmitted to a room designed for privacy or comfort. The noise may come from rooms above or below the occupied space, or from an outdoor noise source. In fact, several of the above named methods only offer a three to ten decibel improvement in acoustical performance over that of standard construction techniques that give no regard to acoustical isolation. Such a small improvement represents from a just noticeable difference to an incremental improvement, but not a soundproofing solution. A second concern with the above named techniques is that each involves the burden of either additional (sometimes costly) construction materials or extra labor expense due to complicated designs and additional assembly steps.

More recently, an alternative building noise control product having laminated panels utilizing a viscoelastic glue has been introduced to the market. Such panels are disclosed and claimed in U.S. Pat. No. 7,181,891 issued Feb. 27, 2007 to the assignee of the present application. This patent is hereby incorporated by reference herein in its entirety. The laminated panels disclosed and claimed in the '891 patent include gypsum board layers assembled into a single soundproof assembly. The advantage of these laminated panels is that they eliminate the need for additional materials such as resilient channels, mass loaded vinyl barriers, and additional layers of drywall during initial construction. The resulting panel improves acoustical performance over the prior art panels by ten or more decibels in most cases and does so without the need for additional layers of construction materials or costly additional labor. However, the described panels are, in general, only optimized with regard to acoustics, with little regard to other material attributes, such as structural integrity. In all of these panels, one or more viscoelastic adhesives (for damping) are incorporated into the laminated panel solely for the purposes of damping and panel adhesion. As will be demonstrated below, such adhesive is designed to damp sound energy but may exhibit poorer performance with regard to panel shear resistance, creep of layers across each other, or the integrity of laminate after cutting the panel into smaller subpanel elements. The term subpanel refers to the fact that, often times, panels are cut to a fraction of the whole panel dimension to accommodate the dimensions and details of real rooms. For this reason, these prior art damped panels compromise the laminates' integrity in terms of the best acoustic energy isolation across its entire face.

A figure of merit for gauging the sound attenuating qualities of a material or method of construction is the material's Sound Transmission Class (STC). STC is a rating which is used to rate partitions, doors and windows for their effectiveness in reducing the transmission of sound. The STC rating is a result of acoustical testing, being derived from a best fit to a set of curves that define the sound transmission class. The test is conducted in such a way that the resulting measurement of the partition is independent of the test environment. The STC is therefore a number for the partition performance only. The STC measurement method is defined by ASTM E90 “Standard Test Method Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements,” and ASTM E413 “Classification for Sound Insulation,” used to calculate STC ratings from the sound transmission loss data for a given structure. These standards are available on the Internet at http://www.astm.org.

A second figure of merit is the panel's structural integrity. For some embodiments of the present invention, one or more test methods may be employed to determine the structural integrity of the damped panels. Such tests are designed to investigate the use of a combination of a structural adhesive and a visco-elastic adhesive to improve the stability of damped panels. The test methods may include the following separate tests performed on the structures: an adhesive bond strength test, a stack holding strength test, a creep resistance test, and a shear strength test. In a stack holding strength test, the materials are formed under normal manufacturing conditions and stacked under weight, for drying. The specimens to be tested are supported by one another and by a number of gypsum risers (4 in some embodiments of the test method) at the base of the stack.

The stack holding strength test may include the arrangement of a large number of panels stacked in a lift. This stack may hold for example thirty to fifty panels, or more. The stack is then placed without end-caps or strapping.

The additional creep resistance test may include one board taken from the damped panel stack and leaned against a wall at a 20 degree angle. The board is left to sit under its own weight and the movement of the unrestrained top half of the board is monitored and recorded at regular intervals (e.g. twelve hours apart), until an offset between the two halves of the panels reaches one quarter inch. The time required to reach such offset is recorded. Typically, a board left overnight (i.e. for over 12 hours) that shows no sign of an offset is qualified under this test protocol.

For the shear strength test, several panels are glued together in a stack and allowed to dry. In some cases, the panels in the stack are about 10 ft long. The stack is then lifted and lowered with a forklift, ten times. The forks on the forklift are set closely together (e.g. at six inches apart from each other). This test subjects the adhesive bond to bending stresses higher than those that would normally be encountered during typical panel transport and bulk handling. The conditions of the boards are monitored while the boards are elevated. If the ends of the boards are offset, then the adhesive has failed, which allowed the panel halves to slide across each other. For the purposes of evaluation, the board is then split and the adhesive bond is viewed to see if the failure occurred in the substrate or the adhesive.

A final evaluation method is the adhesive bond strength test. The adhesive bond strength test tests the bond of the adhesive to the substrate, as compared to the internal structural strength of the substrate. In some embodiments, a wooden dowel or handle is glued to a paper faced gypsum board and bare gypsum substrate, using the adhesive under test. After curing the adhesive, the wooden dowel or handle is torn from the substrate by pure tension; the resulting two pieces are analyzed to see if some of the substrate was pulled off by the adhesive. The amount of adhesive failure is measured by the ratio of the area of the substrate that is not removed and remains intact, to the total area of the adhesive. Typically, a structure is qualified as passing this test when more than 95% of the substrate area covered by the glue is removed upon strain-induced bond failure.

Accordingly, what is needed is a new building construction material and a new method of construction that allows for the maximum reduction of noise transmission at low frequencies, high frequencies, or both simultaneously, while also providing structural integrity. What is needed is a panel designed to optimize both the acoustical and structural performance in typical lightweight frame construction.

SUMMARY OF THE INVENTION

In accordance with some embodiments of the present invention, a new laminated panel and an associated manufacturing process are disclosed which significantly improves the ability of a wall, ceiling, floor or door to resist the transmission of noise from one room to an adjacent room, or from the exterior to the interior of a room, or from the interior to the exterior of a room while maintaining a superior panel structural integrity.

In one embodiment the panel comprises a lamination of several different materials and multiple adhesive formulations. In accordance with one embodiment, a laminated substitute for drywall comprises a first layer of selected thickness gypsum board which is glued to a second layer of selected thickness gypsum material. The first adhesive has a low shear modulus of about 5.0×10³ Pascals, designed to achieve maximum damping across the typical range of noise frequencies (about 100-4000 Hz). This first adhesive is applied across the majority of the first gypsum layer. In addition to the first viscoelastic adhesive, a second adhesive is applied around the perimeter area and typical nailing regions of the panel. The second adhesive layer has a much higher shear modulus of about 1.0×10⁸ Pascals, typical of a commercial structural adhesive. In one embodiment, the second adhesive is applied in one inch wide stripes along the long axis of the panel at 24 inch intervals (three stripes total). These stripes correspond to the approximate locations of the supporting studs (wood or metal) in a lightweight wall construction in which the studs are spaced at 24 inch intervals. The first adhesive may be a specially formulated QuietGlue® adhesive, which is a viscoelastic material available from Serious Materials, 1250 Elko Drive, Sunnyvale, Calif. 94089. In addition to the typical chemicals that make up the QuietGlue® adhesive, additional plasticizing compounds may be added to aid the shift of the shear modulus to achieve maximum damping at a target range of frequencies, according to some embodiments of the present invention. The second adhesive may be one of many commercially available structural adhesives including, but not limited to: Liquid Nails, manufactured by Akzo Nobel Paints of Amsterdam, Netherlands; Beats The Nail, manufactured by DAP of Baltimore, Md.; PL Adhesive, manufactured by Henkel Corporation of Dusseldorf, Germany, or other similar glues.

Formed on the interior surfaces of the two gypsum boards, the glue layer is about 1/32 inch thick. In one instance, a 4 foot×8 foot panel consisting of two 5/16 inch thick gypsum wall board panels, laminated together using a 1/32 inch thick layer of glue, has a total thickness of approximately ⅝ inch. When used on both sides of a standard single wood stud frame, the assembly has an STC value of approximately 54. For comparison, a similar wall assembly constructed with ½ inch thick standard gypsum wallboard has an STC rating of approximately 34. The result is a reduction in noise transmitted through the wall structure of approximately 20 decibels, compared to the same structure using common (untreated) gypsum boards of equivalent mass and thickness, and construction effort.

BRIEF DESCRIPTION OF THE DRAWINGS

This invention will be more fully understood in light of the following drawings taken together with the following detailed description in which:

FIG. 1 shows a perspective view of an embodiment of a laminated panel fabricated in accordance with this invention for minimizing the transmission of sound through the material, while maintaining the superior structural integrity of the panel.

FIG. 2 shows a cross-section view of an embodiment of a laminated panel fabricated in accordance with this invention for minimizing the transmission of sound through the material, while maintaining the superior structural integrity of the panel.

FIG. 3 shows a cross-section view of another embodiment of a laminated panel fabricated in accordance with this invention for minimizing the transmission of sound through the material, while maintaining the superior structural integrity of the panel.

FIG. 4 a-c show plan views of possible glue patterns for the two adhesives in accordance with this invention for minimizing the transmission of sound through the material, while maintaining the superior structural integrity of the panel.

FIG. 5 a-c show plan views of alternate possible glue patterns for the two adhesives in accordance with this invention for minimizing the transmission of sound through the material, while maintaining the superior structural integrity of the panel.

FIG. 6 shows a plan view of a wall structure built using laminated panels as disclosed in FIG. 1.

FIG. 6 a shows a cross sectional view of a wall structure built using laminated panels as disclosed in FIG. 1.

FIG. 7 a shows a plan view of a laminated panel built according to some embodiments of the present disclosure, with structural adhesive dots placed along the long edges of the panel, and a viscoelastic glue covering the rest of the panel area.

FIG. 7 b shows a plan view of a laminated panel using a viscoelastic glue for improved sound isolation performance, with no structural adhesive.

FIG. 7 c-d show a plan view and a cross sectional view, respectively, of a wall structure built using laminated panels as disclosed in either of FIG. 7 a and FIG. 7 b.

FIG. 8 shows a noise transmission chart with test results for two wall structures built according to some embodiments of the present disclosure.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

The following detailed description is meant to be exemplary only and not limiting. Other embodiments of the present disclosure, such as the number, type, thickness, dimensions, area, shape, and placement order of both external and internal layer materials, will be obvious to those skilled in the art, in view of this description.

The process for creating laminated panels in accordance with some embodiments of the present disclosure takes into account many factors: exact chemical composition of the glue; pressing process; and drying and dehumidification process. The descriptions and embodiments that will be given hereafter are exemplary in nature, and it should be understood that variations in size, dimensions, shapes, and relative quantities of materials and compositions will be obvious for one of ordinary skill in the art, based on the following description.

FIG. 1 shows laminated panel 100 according to one embodiment of the present disclosure. In FIG. 1, the layers in the panel are described from top to bottom with the panel oriented horizontally as shown. It should be understood, however, that the laminated panel according to some embodiments of the present disclosure will be oriented vertically when placed on vertical walls and doors, as well as horizontally or even at an angle when placed on ceilings and floors. Therefore, the reference to top and bottom layers is to be understood to refer only to these layers as oriented in FIG. 1 and not in the context of the vertical or other use of this panel. In FIG. 1, reference character 100 refers to the entire laminated panel. A top layer 102 is made up of a standard gypsum material and in one embodiment is 5/16 inch thick.

A second gypsum board layer 104 is placed below layer 102. In one embodiment, second gypsum board layer 104 is 5/16 inch thick. Between gypsum boards 102 and 104 a patterned layer of a first glue 106, and a second glue 108 are provided. The two glue layers serve two different purposes and therefore have different formulations. The first glue 106 includes a viscoelastic polymer modified with additives to optimize the sound dissipation at the audible range of frequencies. The first glue 106 has an extremely low shear modulus of about 10² to 10⁶ Pascals; typically, the shear modulus of a viscoelastic glue with improved sound dissipation characteristics is less than 10⁴ Pascals. An exemplary embodiment of a viscoelastic glue is described in detail below. Conversely, the second glue 108 is a structural adhesive with a very high shear modulus of 10⁶ Pascals or more. One example of such glue, which is commercially available, is called Liquid Nails adhesive from Akzo Nobel Paints of Amsterdam, Netherlands. The shear modulus for Liquid Nails is 1×10⁶ wet, and 2×10⁶ dry. The patterns of the first glue 106 and the second glue 108 are located such that the second glue 108 lies over the expected structural framing locations (joists and studs) whereas the first glue 106 is located in the large areas between expected structural framing locations. These will be further described in later figures. Glue layers 106 and 108 may have a thickness from about 1/64 inch to about ⅛ inch thickness although other thicknesses may be used. Areas where the second glue 108 is placed, are separated by a selected distance 110.

FIG. 2 shows the same laminated panel 100 shown in a cross section view. As with FIG. 1, a top layer 102 is made up of a standard gypsum material and in one embodiment is 5/16 inch thick. Of course, many other combinations and thicknesses can be used for any of the layers, as desired. The thicknesses are limited only by the acoustical attenuation (i.e., STC rating) desired for the resulting laminated panel and by the weight of the resulting structure which will limit the ability of workers to install the laminated panels on walls, ceilings, floors and doors for its intended use. Alternatively, layer 102 may be any one of a layer of cement-based board, wood, magnesium oxide-based board or calcium silicate board. A second gypsum board layer 104 is placed below layer 102. In one embodiment is 5/16 inch thick. In addition to gypsum as a panel material, 104 may be any one of a layer of cement-based board, wood, magnesium oxide-based board or calcium silicate board. Next, between gypsum boards 102 and 104 is a patterned layer of two glues 106 and 108. Glue layers 106 and 108 may have a thickness from about 1/64 inch to about ⅛ inch thickness although other thicknesses may be used. The glue layers are placed in different locations (do not overlap) but share the same horizontal plane. The patterns of the two glue types 106 and 108 are located such that glue 108 lies over the expected structural framing locations (joists and studs) whereas 104 is located in the large areas between expected structural framing locations. In FIG. 2, glue 108 is in stripes about 1 to 2 inches wide, spaced at a selected distance 110. For typical residential construction, wall studs are placed at 16 inch intervals throughout the home. Therefore, distance 110 is 16 inches in order to place the structural glue stripes 108 in alignment with the wall studs. These stripes are also important because if the panel is cut or trimmed for field installation the reduced-area subpanel will rely on glue 108 for lamination integrity. The trimmed panel may then be placed in the building structure such that the glue stripes 108 are aligned with the framing members.

Between the structural members where the panels are fastened with nails or screws, the panel is free to vibrate and does so when subjected to a sound field. In this vibrating region of the panel, the first glue 106, which is viscoelastic, is placed. Typically, the first glue 106 is made of the materials as set forth in TABLE 1, although other glues having similar characteristics to those set forth directly below Table 1 can also be used in some embodiments of the present disclosure.

An important characteristic of the first glue composition and the overall laminated panel is the shear modulus of the first glue, when cured. The shear modulus can be modified from 10² to 10⁶ N/m² (or Pascals) depending on the frequency range of interest for noise attenuation, with the given materials provided within the given ranges listed in Table 1.

TABLE 1 QuietGlue ® Adhesive Chemical Makeup WEIGHT % COMPONENTS Min Max Preferred acrylate polymer 33.0% 70.0%   60% ethyl acrylate, methacrylic 0.05% 3.00% 0.37% acid, polymer with ethyl-2- propenoate hydrophobic silica 0.00% 0.500%  0.21% paraffin oil 0.10% 4.00% 1.95% silicon dioxide 0.00% 0.30% 0.13% sodium carbonate 0.01% 1.50% 0.66% stearic acid, aluminum salt 0.00% 0.30% 0.13% surfactant 0.00% 1.00% 0.55% rosin ester 1.00% 9.00% 4.96% water 25.0% 40.0% 30.9% 2-Pyridinethiol, 1- 0.00% 0.30% 0.17% oxide,sodium salt The preferred formulation is but one example of a viscoelastic glue. Other formulations may be used to achieve similar results and the range given is an example of successful formulations investigated here.

The physical solid-state characteristics of QuietGlue® adhesive include:

-   -   1) a broad glass transition temperature below room temperature;     -   2) mechanical response typical of a rubber (i.e., elongation at         break, low elastic modulus);     -   3) shear modulus between 10² and 10⁶ N/m² at room temperature;     -   4) does not dissolve in water (swells poorly); and     -   5) peels off the substrate easily at the temperature of dry ice.

QuietGlue® adhesive may be obtained from Serious Materials, 1250 Elko Drive, Sunnyvale, Calif. 94089.

Because of the desired low shear modulus of first glue 106, a panel laminated exclusively with this adhesive will have problems remaining well bonded under a range of environments and conditions. Further, the external layers 102 and 104 may creep or be displaced across each other when stored at an angle or when subjected to mild curvature. For this reason, glue 108 is used to hold the panels in place under any condition.

FIG. 3 shows another embodiment of the present disclosure which incorporates an internal constraining layer 312. As shown in FIGS. 0.1 and 2, top and bottom layers 102 and 104 are made up of a standard gypsum material and in one embodiment are 5/16 inch thick. Alternately, layers 102 and 104 may be any one of a layer of cement-based board, wood, magnesium oxide-based board or calcium silicate board. Applied to the bottom surface of layer 102 is a plane of the first glue 106, which is viscoelastic and the second glue 108, which is a structural adhesive. In the same manner shown in FIG. 2, the stripes of second glue 108 are spaced at a selected distance 110. The first glue 106 is located in the regions between the distances 110. On the upper surface of layer 104 is a plane of viscoelastic glue 106-1 and structural adhesive 108-1. Glues 106-1 and 108-1 have the same formulation and applied in the same pattern as first glue 106 and second glue 108, respectively.

Referring to FIGS. 1-3, the width of the stripes of second glue 108 should be sufficient to provide structural integrity to the panel prior to its installation on the frame. Typically, a stripe of about ½ to 1½ inches is enough for this purpose. A width that is significantly smaller than ¼ inches should be avoided, specifically, no less than ⅛ inches. In addition, the width of the stripes of second glue 108 should not exceed a certain value, because otherwise this may compromise the sound absorbing and sound attenuation properties of glue layer 106. This is described in detail in U.S. patent application Ser. No. 11/734,770, assigned to the assignee of the present application and incorporated herein by reference in its entirety. Specifically, the width of the stripes of second glue 108 should be such that no less than 20% of the total surface area of the panel is covered by glue layer 106. Also, the width of the stripes of second glue 108 should be such that the spacing between the edges of the patches of glue layer 106 is no greater than a half wavelength of sound in the frequency of interest for sound attenuation of the panels. In one embodiment of the present disclosure, the width of the stripes of second glue 108 is no greater than 2 inches.

Adjacent to glue layers 106 and 108 is a constraining layer 312 made up of gypsum, vinyl, steel, wood, cement or another material suitable for the application. If layer 312 is vinyl, the vinyl is mass loaded and, in one embodiment, has a surface density of one pound per square foot or greater. Mass loaded vinyl is available from a number of manufacturers, including Technifoam, of Minneapolis, Minn. The constraining layer 312 may improve the sound attenuation and physical characteristics' of a laminated panel so constructed.

In some embodiments of the present disclosure, constraining layer 312 may be galvanized steel of a thickness such as 30 gauge (0.012 inch thick). Steel has a higher Young's Modulus than vinyl and thus can outperform vinyl as an acoustic constraining layer. However, for other ease-of-cutting reasons, vinyl can be used in the laminated panel in place of steel. Cellulose, wood, plastic, cement or other constraining materials may also be used in place of vinyl or metal. The alternate material can be any type and any appropriate thickness. In the embodiment depicted in FIG. 3, the constraining material 312 approximates the size and shape of the glue layers 106 and 108 to which it is applied. Some embodiments may provide a constraining layer 312 with a size and shape approximating those of external panels 102 and 104.

FIGS. 4 a-c show the glue plane in plan view with various patterns. In FIG. 4 a, the structural adhesive areas covered with the second glue are shown as 402 and 408. The viscoelastic adhesive areas covered with the first glue are shown as regions 404, in between stripes 402 (FIGS. 4 a-b), or surrounding the patterns of second glue 402 (FIG. 4 c). Structural glue stripes 402 are separated by a selected distance 406. Distance 406 would be 16 inches for a 48 inch wide panel, which is a standard panel dimension in the construction industry. Structural glue stripes 408 correspond to the locations of the “top plate” and “bottom plate,” which are structural members present in typical framed construction. FIG. 4 b shows the same glue pattern, but with the “top plate” and “bottom plate” structural adhesive stripe 408 not present. In FIG. 4 c, instead of structural adhesive stripes, the structural adhesive 402 is applied as intermittent spots or circles. These are also spaced at a selected distance 406 corresponding to the spacing of the structural framing members. Region 404 is the location of the viscoelastic glue.

The embodiments depicted in FIGS. 5 a-c are similar to those of FIGS. 4 a-c as they show the glue plane in plan view with various patterns. In FIGS. 5 a-c, the selected distance 506 corresponds to the interval of structural framing members typical of commercial (non-residential) construction. In FIG. 5 a, the structural adhesive areas covered with the second glue are shown as 502 and 508. The viscoelastic adhesive areas covered with the first glue are shown as the regions 504, in between stripes 502. Structural glue stripes 502 are separated by a distance 506. Distance 506 would be 24 inches for a 48 inch wide panel, which is a standard panel dimension in the construction industry. Structural glue stripes 508 correspond to the locations of the “top plate” and “bottom plate,” which are structural members present in typical framed construction. FIG. 5 b shows the same glue pattern, but with the “top plate” and “bottom plate” structural adhesive stripes 508 not present. In FIG. 5 c, instead of structural adhesive stripes, the structural adhesive 502 is applied as intermittent spots or circles. These are also spaced at a selected distance 506, corresponding to the spacing of the structural framing members. Region 504 is the location of the viscoelastic glue.

Referring to FIGS. 4 a-c and FIGS. 5 a-c, the width of the stripes and glue areas of second glue 402 (FIGS. 4 a-c) and 502 (FIGS. 5 a-c) should be sufficient to provide structural integrity to the panel, prior to its installation on the frame. Typically, a stripe or glue area of about ½ to 1½ inches in width or diameter is enough for this purpose. A width or diameter that is significantly smaller than ¼ inches should be avoided, more specifically, no less than ⅛ inches. In addition, the width of the stripes or the diameter of the area of second glue 402 and 502 should not exceed a certain value, because otherwise this may compromise the sound absorbing and sound attenuation properties of glue layer 404 and 504. Specifically, the width of the stripes or the diameter of the area of second glue 402 and 502 should be such that no less than 20% of the total surface area of the panel is covered by glue layer 404 and 504. Also, the width of the stripes or the diameter of the area of second glue 402 and 502 should be such that the spacing between the edges of the patches of glue layer 404 and 504 is no greater than a half the wavelength of sound in the attenuation frequency of interest for sound attenuation of the panels. In one embodiment of the present disclosure, the width of the stripes or the diameter of the area of second glue 402 and 502 is no greater than 2 inches.

Continuing to refer to FIGS. 4 a-c and FIGS. 5 a-c, some embodiments of the present invention may have glue patterns 402 and 502 oriented perpendicularly with respect to the illustrated pattern. That is, the short side of the panel would be the vertical edge, and the long side of the panel would be the horizontal edge of the panel, keeping the lateral distances 406 and 506 between stripes and rows of glue patterns 402 and 502, respectively, along the horizontal direction. As previously stated, distances 406 and 506 correspond to the spacing of the structural framing members to which the panels will be attached.

Referring to FIGS. 6 and 6 a, a typical framed wall assembly 600 is shown. FIG. 6 shows a plan view of wall assembly 600, and FIG. 6 a shows a cross-sectional view of wall assembly 600. This assembly includes a front side 610 which is constructed using a material such as laminated panel 100 disclosed in FIG. 1, and a rear panel 608 which is a single layer of type X gypsum wallboard. Panels 608 and 610 are attached to 2×4 studs 602, 604 and 606. These will be better appreciated by reference to the cross sectional view of FIG. 6 a. Batt-type or blown-in thermal insulation 612 is located in each of cavities 618 and 620 which are enclosed between the 2×4 stud structures. The structural adhesive according to some embodiments of the present disclosure will correspond to the center lines of studs 602, 604, and 606.

FIG. 7 a shows a plan view of a laminated panel 700A, built according to some embodiments of the present disclosure. In one implementation, panel 700A has a width 706 of four (4) feet, and a length 707 of eight (8) feet, and is built with laminated layers as depicted in FIGS. 1 and 2, including top layer 102, bottom layer 104, and a glue layer comprising a patterned layer of a first glue 702 and a second glue 704. The first glue 702 includes a viscoelastic polymer as in first glue 106 of FIG. 1, and the second glue 704 includes a structural adhesive as in second glue 108 of FIG. 1. Structural adhesive 704 is placed along each of the long edges of the panel, at intervals 708 of two feet. In the embodiment depicted in FIG. 7 a, second glue 704 is applied in circular areas containing about 0.4 ml of adhesive each. The rest of the surface area of the glue layer is covered uniformly with viscoelastic glue layer 702.

FIG. 7 b shows a plan view of a laminated panel 700B, having dimensions 706 and 707 as in FIG. 7 a, except that the laminated structure of panel 700B includes only a viscoelastic glue layer 702, covering the entire surface of the panel. Panel 700B is built according to one embodiment of the present disclosure in which two external layers of a selected material are separated by a layer of viscoelastic glue 106 placed between them. Panel 700B may be constructed according to FIG. 1. That is, first glue 106 covers the entire surface area in between external layers 102 and 104, without using second glue 108. In some embodiments of Panel 700B, the two external layers are two layers of gypsum, and the viscoelastic glue is a glue (i.e. first glue 106), made of materials as set forth in TABLE 1. The viscoelastic glue of panel 700B may have a shear modulus between 10² to 10⁶ N/m² (or Pascals). Panel 700B may achieve maximum reduction of noise transmission at low frequencies (e.g. between 60 Hz and 500 Hz), at high frequencies (e.g. between 500 Hz and 8000 Hz), or at both low frequencies and high frequencies simultaneously.

FIGS. 7 c and 7 d show plan and cross sectional views of framed wall assembly 720. Assembly 720 includes a front side 710 and a back side 708, which are constructed using a material such as laminated panel 700A, disclosed in FIG. 7 a. In some embodiments of the present disclosure, framed wall assembly 720 may include laminated panels 700B in the front side 710 and the back side 708. Panels 708 and 710 are attached to 2×4 studs 702, 704 and 706. Assembly 720 will be better appreciated by reference to the cross sectional view of FIG. 7 d. The structural adhesive 704 of framed wall assembly 720, when a laminated panel 700A (cf. FIG. 7 a) is used in the front side 710 and the back side 708 of wall assembly 720, will be aligned to the center lines of studs 702 and 706.

FIG. 8 shows the results of a noise transmission test performed according to test protocol ASTM E90 on framed wall assembly 720 under two different test conditions. In case 800A, laminated panels 710 and 708 of framed wall assembly 720 are provided by laminated panel 700A. In case 800B, laminated panel 700A is replaced by laminated panel 700B in both panels 710 and 708 of framed wall assembly 720. The result, as show in FIG. 8, is that laminated panels 700A performed identically to laminated panels 700B (i.e., rendering an STC value of 47), with only statistically insignificant differences between the two cases. The conclusion derived from the data shown in FIG. 8 is that the addition of structural adhesive areas to laminated panels according to the embodiments disclosed in the present disclosure has no effect upon the acoustic performance of laminated panels constructed with viscoelastic glue, according to the embodiments disclosed herein.

As one of regular skill in the art of building construction would realize, the dimensions given for each material in the laminated panels according to some embodiments of the present disclosure can be varied in view of cost, overall thickness, weight and desired sound transmission properties, without affecting the overall sound attenuation performance and structural integrity of the panels.

The above-described embodiments and their dimensions are illustrative only, and not limiting. In addition, other embodiments of the present disclosure will be obvious in view of the above description. 

What is claimed is:
 1. A laminated panel for use in building construction as part of a wall, floor, ceiling, or door, said panel comprising: a first external layer of material; a first layer of glue placed adjacent to the first layer of material; a second external layer of material placed on the other side of the first layer of glue; wherein the first layer of glue comprises a viscoelastic glue formed in a first pattern and a structural adhesive glue formed in a second pattern; wherein the first pattern and the second pattern are non-overlapping and are provided on the same plane.
 2. The laminated panel of claim 1, further wherein: the viscoelastic glue has a shear modulus between 10² Pascals to 10⁶ Pascals; and the structural adhesive glue has a shear modulus between 10⁶ Pascals and 10⁸ Pascals.
 3. The laminated panel of claim 2, further comprising: a perimeter area and nailing regions for attaching the panel to a structural component of a building, wherein the second pattern covers the perimeter area and the nailing regions of the panel.
 4. The laminated panel of claim 2, further wherein: the first pattern covers an area within the areas between the structural framing locations of the panel; and the second pattern covers an area that overlaps with structural framing locations of the expected assembly.
 5. The laminated panel of claim 2, further wherein: the second pattern comprises an array of vertical stripes that have a center to center separation of 24 inches, and further wherein each stripe has a width no less than about ⅛ of an inch, and no greater than about 2 inches.
 6. The laminated panel of claim 2, further wherein: the second pattern comprises an array of vertical stripes that have a center to center separation of 16 inches, and further wherein each stripe has a width no less than about ⅛ of an inch, and no greater than about 2 inches.
 7. The laminated panel of claim 2, further wherein: the second pattern comprises an array of vertical stripes that have a center to center separation of 48 inches, and further wherein each stripe has a width no less than about ⅛ of an inch, and no greater than about 2 inches.
 8. The laminated panel of claim 1, further wherein the first pattern of glue and the second pattern of glue are selected such that the first pattern of glue covers an area no less than 20% of the total surface area of the panel.
 9. The laminated panel of claim 1, further wherein the first pattern of glue and the second pattern of glue are selected such that the first pattern of glue comprises shapes having edges wherein the distance between the edges of two different shapes is no greater than ½ the wavelength of sound in the attenuation frequency of interest; and the second pattern of glue comprises shapes with a diameter no less than ⅛ of an inch.
 10. The laminated panel of claim 1, further wherein: at least one of the first and second external layers of material comprises a layer of gypsum.
 11. The laminated panel of claim 1, further wherein: at least one of the first and second external layers of material is selected from the group consisting of wood, cement-based board, magnesium oxide-based board, and calcium silicate board.
 12. A laminated panel for use in building construction as part of a wall, floor, ceiling, or door, said panel comprising: a first external layer of material; a first layer of glue placed adjacent to the first layer of material; a second external layer of material placed on the other side of the first layer of glue; wherein the first layer of glue comprises a viscoelastic glue having a shear modulus between 10² Pascals to 10⁶ Pascals.
 13. A laminated panel for use in building construction as part of a wall, floor, ceiling, or door, said panel comprising: a first external layer of material; a first layer of glue separating the first layer of material from at least one internal constraining layer of material; a second layer of glue separating the at least one internal constraining layer of material from a second external layer of material; wherein at least one of the first and second layers of glue comprising a viscoelastic glue formed in a first pattern; and a structural adhesive glue formed in a second pattern; wherein the first pattern and the second pattern are non-overlapping, and are provided on the same horizontal plane.
 14. The laminated panel of claim 13 wherein the at least one constraining layer of material is selected from the group consisting of: gypsum, vinyl, steel, wood, cement, cellulose, plastic, and metal.
 15. The laminated panel of claim 14 wherein the at least one constraining layer of material is further selected from the group consisting of steel and galvanized steel.
 16. A building structure for use as part of a wall, floor, ceiling or door, comprising: two panels attached to a structural frame; wherein at least one panel comprises a laminated panel; said laminated panel further comprising: a first external layer of material; a first layer of glue placed adjacent to the first layer of material; a second external layer of material placed on the other side of the first layer of glue; wherein the first layer of glue comprises a viscoelastic glue formed in a first pattern and a structural adhesive glue formed in a second pattern; wherein the first pattern and the second pattern are non-overlapping and are provided on the same horizontal plane.
 17. A building structure for use as part of a wall, floor, ceiling or door, comprising: two panels attached to a structural frame; wherein at least one panel comprises a laminated panel; said laminated panel further comprising: a first external layer of material; a first layer of glue separating the first layer of material from at least one internal constraining layer of material; a second layer of glue separating the at least one internal constraining layer of material from a second external layer of material; wherein at least one of the first and second layers of glue comprises a viscoelastic glue formed in a first pattern and a structural adhesive glue formed in a second pattern; wherein the first pattern and the second pattern are non-overlapping and are provided on the same horizontal plane.
 18. A building structure for use as part of a wall, floor, ceiling or door, comprising: two panels attached to a structural frame; wherein at least one of the panels comprises a laminated panel; said laminated panel further comprising: a first external layer of material; a first layer of glue placed adjacent to the first layer of material; a second external layer of material placed on the other side of the first layer of glue; wherein the first layer of glue comprises a viscoelastic glue having a shear modulus between 10² Pascals to 10⁶ Pascals.
 19. A method for making a laminated panel for use in building construction as part of a wall, floor, ceiling or door, and further comprising: placing a first external layer of material; placing a first layer of glue adjacent to the first layer of material; placing a second external layer of material on the other side of the first layer of glue; wherein placing the first layer of glue comprises forming a viscoelastic glue in a first pattern and a structural adhesive glue in a second pattern; wherein the first pattern and the second pattern are non-overlapping and are provided on the same horizontal plane. 